HZJ75 1997: I think my clutch exploded........

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cruisers75100

cruisers75100

10 Year
Joined
Oct 20, 2011
Threads
10
Messages
100
Location
Brisbane QLD Australia
Hello everyone ,

Last week I had to park my 75 series up for a few days while I went down the coast, I took my 100 series for a run.....

Yesterday I was servicing the hungry when I decided I should be changing the transfer and diff oil. Jumped in my 75 and decided to go get some more oil..... I didn't get very far

I drove up my driveway and noticed that the ol girl was blowing a bit more black smoke than normal when cold, when I got to my street I throttled down, looked in the mirror and it was bellowing black smoke then all of a sudden .... Bang!!!! Something exploded . I rolled to a stop, engine was running fine but I have no gears in high range, low range, all gears, got nothing!

Where I live is on acreage, I had a neighbor walk over to me saying he heard the bang from inside his shed. It was pretty severe!

I walked back home and grabbed the hungy to tow It back home, after winching into the shed I have noticed the rear passenger side axle studs have all been sheared off , the axle was hanging out of the hub nearly an inch!

Removed back wheels. And started it up, rear wheel is spinning ok off the ground! When It happened out on the street I stuck it in gear and had a look underneath to see if the tailshaft was moving.... It wasn't .

I have now checked all oils and they look fine! 2 years ago I had a safari tuff clutch installed , it's had a noisy throw out bearing for some time now!

Am I heading down the right path thinking its the clutch? It's almost like some bearing has seized while sitting and has crapped itself hard ?? I recently spent nearly a month on Fraser island , a couple of times over there towing in soft sand I smoked the clutch up really bad !

Obviously this is going to be a s*** job on the shed floor, 1 person! Any tips to removing gearbox and clutch? I haven't done this before but I'll give anything a go... I do have a couple of trolley jacks and can go get a gear box stand if you think it will help ?

Any tips to help me attack this job would be great??

Will post pics as they come to hand !

Thanks in advance!
 
More questions guys......

Do I have to remove the transfer case and gear box as one . Or can I move the transfer back allowing the gear box to drop down?

Below is a pic of the axle studs .... Everyone broken!

Cheers

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Sent from my iPhone using IH8MUD
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From what I hear axel studs go a fair bit, usually due to large tyres, I'm running thirty dives, hasn't happened to me, fingers xrossed
 
Hi all, update time!

Well now I'm a bit stumped on what my problem actually is .

I removed the gear box and transfer case today , it pretty much fell out actually , I have no idea how I'm going to get it back in .... Heavy little f@&kers aren't they !!

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When I removed the box the throw out bearing was sitting in the bottom of the bell housing , I suspect this to be normal when removing the box ..

Removed the starter and bell housing , then proceeded to disassemble the clutch, seem to be in ok condition, nothing broken that I can see!



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I haven't removed the flywheel yet .. Not sure where to go from here! The thing I'm worried about Is I have a very thin layer of fine metal filing over the entire engine bay ??



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Not sure what has happened here yet !

Why did I brake all the axle studs ? Is that a secondary problem ?

With the gear box out it feels ok selects every gear and high/low range is working !

The rear diff feels ok , nice n smooth !

Metal filings through the engine bay WTF ??

Sent from my iPhone using IH8MUD
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Can't help you with the axle studs breaking, although it does sound like something has locked the drivetrain up.
But when you put the g/box back in grab a couple of small ratchet straps and strap it down to the jack so it doesn't move around or fall on you
 
the disc looks fine
the PP definately has some burning, should either replace or get turned.
replace the throwout and pilot, rear main and turn the flywheel

i will take pics of the "backyard" adapter i made a couple decades back for removing the tranny and t/case. works on 4 speed and 5 speed tranny with 2 peice tcases. it makes R&R a breeze for one person.

with the rear shaft sheered off all your power is going to a dead axle (unless locked). you mention the rear drive shaft wasn't turning in gear, which is a head scratcher, unless you had the t/case in neutral by accident during the test.

i suspect the bang was all the studs breaking off at once
but
for a test, put the tranny in gear, put the t/case into 2wd H and turn the rear output, it will turn but it shoudl be tough since you are turning all the gears in the t/case as well as the gears in the tranny. make sure the input shaft into the tranny is turning while you are turning the output flange.
there is a slim chance you busted a gear in the t/case.

did you by chance have the rear locker engaged for a while? if so then this would explain the studs shearing off. weakest link and all that.

just trying to help
cheers
 
Hi Crushers,

Mate than you for your reply and advice... Most appreciated

I feel like a dick now, I don't believe there was any reason to remove the box or clutch, I am thinking now that the primary problem was breaking the axle studs, and agree now this was most likely the noise I heard....

As for the drive shaft not turning , you may be correct in saying the transfer was in neutral, maybe somehow it did come back to neutral wen the axle studs broke, maybe in the spur of the moment I put it back to neutral after seeing if low range works.

As you recommend I will have the pressure plate and flywheel skimmed. Will fit a new throw out bearing as well.

Really not looking forward to refitting the gear box, it may not be too bad, time will tell!

I will grab some new axle studs, put it back together and takes her for a run.

3 weeks ago I did a major brake and bearing service on the truck..... I'm now thinking the rear axle studs may have come loose, hense the reason for snapping them off!

In the days of fixing marine motors I was taught to weld onto the broken stud and remove with vice grips....... Does this sound ok for the removal of the broken studs?? I haven't used easy outs before!

Thanks again dude cheers
 
Ya, and I want to see the backyard tool for removing the trans/split case!

Edit: pilot is the bearing on the back of the engine where the input shaft inserts into.
 
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i will take a pic today ...
it looks back yard, spur of the moment butcher build ... but it works and although i built it for a one time use it has stood up for a couple decades now.
will post later.

as 1tontoy said, the pilot is that small bearing in the back of the crank.
putting the tranny/tcase back in is a bitch of a job without a proper jack and 2 hands.
mount to rolling jack securely and LEVEL with the bellhousing.
make sure that darn release bearing is secure to the fork.
make sure the clutch is installed properly using an alignment tool
align the "mountain" of the input shaft teeth to the proper location for the valley of the clutch disc, makes for easier install.
put a tiny amount of grease on the input splines, the input shaft end where it goes into the pilot bearing
put a tiny amount of grease on the bearing collar so the release bearing can move freely on that retainer.
roll the tranny into the bell housing, making sure you get the release bearing over the collar and it doesn't come off the fork
roll ahead till the input shaft slides through the clutch disc, you might need to rotate the input shaft for have the tranny and t/case in gear, this way you can turn the rear output on the t/case which in turn will rotate the input shaft to line up the mountains and valleys of the input gear with the clutch disc. turn slow while gently pushing ahead on the tranny.
once that slides in then it is time to line up on the pilot bearing. this can be a bitch and a half. once you slide through the disc then measure the opening so that you are going directly in and not on an angle.
all 4 corners need to be exact. the biggest cause of pilot bearing failure is the brute force assembly putting undue pressue on the pilot from improper installation of the input shaft.
to get an idea how important and accurate this is, BEFORE installing the pilot into the crank try and install it on the input shaft. it is a very tight fit. try to install at a slight angle and suddenly you see how difficult it will be and why the bearing will be damaged.
i have 2 extra long bolts that i use in the bottom holes of the bellhousing to tranny mount holes. this allows a balance for the tranny while it goes in. seems to work very well.

best of luck in the install.
enough rambling.
cheers
 
Just get a secondhand hub with good studs its a lot easier,any fully floating one will fit,if you have a disc rear end you have to cut a small pice out to ajust the handbreak. i found the aftermarket studs are soft and snap easy. make sure you file the flange on the axel that buolts to the hub to remove any damage or the studs will break again
 
also remember, the studs are to hold the axle in ... NOT to take torsional load, that is the requirement of the pins.
did you use a paper gasket or silicone when reassembling? the latest decision has been, so it seems and i agree with it, that the paper gasket seems to resist the twist better than the silicone which could relate to a lubricant of sorts.
i would be tempted to take Aussie 25 recommendation, or get a second set of oversized pins installed.
if you inspect your hub and see the pins have worn an oblong hole then you have no choice but to replace or drill to oversize ... otherwise it won't be long before it happens again.
 
I agree with crushers on the bang being the studs, my old 75 series would smash studs off all the Time,and when ever they would let go it would be the same loud bang that would skip the heart beat a few times, then the back diff lock in and drive home.
 
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the backyard tool:
i do want to make another one with a leveling nuts on the front section and the side wing. this works well but there are times when it would be nice to fine adjust the angles ...
reinforcement across the front would be nice too, just cause.
picture,
wheeling the next morning, heading out at 5:30 am
at 10 pm the tranny t/case combo fell on my hand for the 3rd painful time, tired, grumpy, hurting ...
so
some scrap metal, a socket that fits the jack and the clutch is changed and ready to wheel

decades later the ugly adapter is still in use.
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your wheel bearings would have to be majorly fawked to tear out the studs.
i had a HZJ75 pickup with the rear bearings completely shot. so bad the inner bearing actually road over the outer and i ended up with the hub/axle/wheel/brake drum sitting outside the body with the truck being supported by the axle that still was slightly inside the axle tube. the studs didn't sheer.
i will call BS on that one.
 
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